Chapter 23

What most strongly influences a mineral's hardness?

The strength of a mineral's chemical bonds.

The difference between cleavage and fracture is

cleavage occurs at planes of weakness, and fractures are random breaks.

The difference between cleavage and crystal form is

cleavage represents how a mineral breaks, and crystal form represents how a mineral grows.

Metamorphic foliation is

a layered appearance caused by minerals that grew in a preferred orientation.

The most characteristic feature of sedimentary rocks is that they

are formed in layered sequences—strata.

The property many metamorphic rocks exhibit by flat or elongated mineral grains in parallel layers is called

foliation

As magma cools, the first minerals to crystallize are those with a

high melting point

The mineral that crystallizes first from a cooling magma is the one with the

highest melting point.

The color of a mineral is predominantly related to

its chemical composition

All of the following occur during metamorphism EXCEPT

melting

Recrystallization can occur when

minerals are subjected to increased temperature and pressure and/or contact with chemically active fluids.

Coarse-grained igneous rocks occur because

minerals cooled and grew over long periods of time.

A mineral's hardness describes

resistance to scratching.

Some ________ rock is formed from minerals that were once dissolved in water.

sedimentary

The basic building block of all silicate minerals is the

silicate tetrahedron.

The physical properties of a mineral are predominantly related to

the chemical composition and the internal arrangement of the atoms that make up the mineral.

The rock cycle describes

the natural recycling of rock from one rock type to another

The silicates are the most common and abundant mineral group because silicon and oxygen are

the two most abundant elements in the earth's crust.

In the crystallization of chemical sediments from a water solution, low-solubility minerals precipitate first because

they are not easily dissolved.

How is erosion different from weathering?

Erosion is the process of removing sediment from weathered rock.

What is the most abundant mineral in Earth's crust?

Feldspar

Which of the following is NOT part of the definition of a mineral?

It has a definite color.

Why is glass is NOT classified as a mineral?

It has an amorphous, rather than crystalline molecular structure.

Which of the following is NOT considered igneous intrusive?

Lava

Coal is a sedimentary rock. What is the source of its sediments?

Ancient plants that grew in swamps and bogs.

Sedimentary rocks cover what percentage of the continental crust?

75%

What is the silicate tetrahedron?

A) The building block of all silicate minerals. B) An ion common to most of the minerals found in Earth's crust. C) A silicon atom bonded to four oxygen atoms in the shape of a tetrahedron.

Even though the temperature at depth is hotter than rock's melting point, the rocks at depth are solid, because

A.) they are under enormous pressure from the rock above. B.) increased pressure prevents their melting. C.) the temperature would have to be even higher to counteract the increase in pressure.

Which of the following pairs of elements makes up over 75% of the Earth's crust?

Oxygen and silicon.

What produces mineral gold?

Precipitation from hydrothermal solutions.

What is the difference between a rock and a mineral?

Rocks are consolidated mixtures of minerals.

Which of the following best describes the difference between rocks and chemical compounds?

Rocks are solid, physical mixtures.

Earth's crust is mostly comprised of minerals from which class?

Silicates.